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Testing Your Disks

By dbott | September 1, 2010

Testing Your Disks

In the event that your ReadyNAS is not functioning properly, it is quite possible that you are suffering from a failing or flaky disk.  Under normal circumstances, the ReadyNAS should detect a failed disk and kick it from the array.  In those cases, you will also receive alerts from the NAS and see information in the log files.

If you are noticing poor performance, frequent lock-ups, re-syncs or volume scans (aka fsck or file-system checks), then you should check your disks thoroughly.

Quick Ways to Check for Disk Problems

Frontview SMART status

Frontview > Status > Health

RAIDar

Check the Status of Your Disks and Volume

It is important to remember that information regarding your disks obtained from SMART status or RAIDar is not a thorough test, nor does it mean that the disks are 100% healthy.  In some instances the disk may be having intermittent read and/or write problems that can cause all sorts of weird issues ranging from a decrease in performance to data re-syncs.  It is also possible that you may not receive any alerts or notification of disk trouble, making it difficult to determine if the disks are actually the problem.

Thorough Tests

Starting in RAIDiator 4.2.9, the x86-based ReadyNAS devices included an option to test the disks in the firmware.  This is an offline utility that will test each disk in sequence and can take a number of hours per disk.  See this post on how to invoke the “Test Disks” option: http://home.bott.ca/webserver/?p=252

Whenever removing disks from your NAS, it is important that you return the disk to it’s original location.  Returning the disk to the wrong slot when the array is degraded can result in catastrophic data loss.  Be sure to label the disks.

Vendor Utilities

For those that don’t have an x86-based ReadyNAS (Ultra, NVX, Pro, 2100, 3100, 3200 & 4200) with the “Test Disks” option, you will need to thoroughly test the disks with the vendor tools in order to eliminate or confirm that they are the source of the problem.  Testing the disks requires the following:

  1. Installation of the suspect disk in a SATA-capable PC:
  2. The hard disk manufacturer’s diagnostic utility (i.e. SeaTools for Seagate drives).
  3. A few hours to run a thorough test for each disk.
  4. SATA Drive Installation

Most of the hard disk vendors offer the utility in a number of versions, such as a bootable CD ISO version, a bootable floppy disk version, as well as a version that can be run from within Windows.  As far as I’m aware, only the Windows version allows the suspect drive to be installed in a portable USB enclosure.  Most of the other versions of the utilities will require you to connect the drive directly to the SATA channel.  Please check with your disk vendor.

SeaTools for Windows

SeaTools for Windows tests SATA, USB, 1394, ATA (PATA/IDE) and SCSI drives. It installs onto your system. SeaTools for Windows is completely data safe. If the drive passes SeaTools for Windows, your troubleshooting can move to other areas.

SeaTools for DOS

SeaTools for DOS tests SATA or ATA drives from a bootable CD-ROM or floppy. It can test a SATA (Serial ATA) or older ATA (PATA/IDE) interface hard drive. Because the software boots to its own operating system you can test your drive regardless of the OS installed on it. You can even test a new or completely blank drive. In addition, this version offers limited repair and data erasure.

The Old “pull one-disk-at-a-time” Trick:

Mac users, as well as those users that only have a notebook/laptop/netbook may need to borrow a friend’s computer or take it to a local computer shop for testing or revert to the old “pull one-disk-at-a-time” trick:

  1. Power off the NAS.
  2. Remove drive 1 (leave 2, 3, 4 in)
  3. Power on the NAS.
  4. See if it boots.
  5. If not, start over at step 1 and replace disk 1 and remove disk 2. Repeat with all drives.

During the boot process, be sure to monitor the NAS with RAIDar.

If you can’t access your data -or- if RAIDar prompts you to configure your NAS (i.e. factory default), power off the NAS before the 10 minute window expires.

Additional Information:

  1. Be sure to only select disks that appear on the Hardware Compatibility List. Using non-approved disks can result in various issues ranging from disks dropping out of the array to catastrophic data loss.
  2. If you are going to use HCL-approved disks that were used elsewhere (such as a computer or other device), be advised that the ReadyNAS will initialize the disk and wipe any data that exists on the disk. In order to get the NAS to initialize the disks, you may need to delete any/all partitions from the disk as the ReadyNAS may detect a valid partition signature on the disk and refuse to initialize it. Even if the disk was working fine previously, you should still take the time to test it.

    Delete Partition in Windows

    Delete Partition in Windows

  3. 4K sector alignment vs. 512-byte (x86-based units: Ultra, NVX, Pro, 2100, 3100, 3200, 4200 & sparc-based units: Duo, X6/600, NV/NV+, 1000s/1100)
  4. Increasing LCC counts – WDIDLE3 utility

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